Hermetic literature, or Hermetica is a body of works in Greek and Latin on philosophical, theological, and occult subjects attributed to Hermes Trismegistos (1) (" thrice-great Hermes "), a Greek name for the Egyptian god Thoth (2), patron of the literary arts and originator of all mystical wisdom. His reputed works are both popular-dealing with alchemy and astrology-and learned-concerning divine revelation and the redemption of humanity through knowledge of God (see gnosticism). Although set in Egypt, the Hermetic writings are entirely Greek in origin and reflect the then-prevalent respect for Egyptian wisdom and occultism. Hermetic literature is frequently alluded to in medieval and Renaissance writing and is now regarded as an important source of information on the social and intellectual history of the early Roman Empire. The caduceus was the wand of Hermes, Greek god of chance and messenger of the Olympian deities. The wand, made of olive wood and gold, was entwined with serpents and surmounted by wings. It possessed magical powers over dreams, waking, and sleep. Hermes placed the wand gently upon the eyes of those who were being summoned to the hereafer, and he carried it as his staff in conducting the dead to the netherworld. The wand originally belonged to Apollo; upon hearing the shepherd's pipe that Hermes played, however, Apollo bargained to exchange the wand for it. The caduceus has become a widely accepted symbol for the medical profession. The more appropriate symbol would be the staff of Asclepius, who was the Greek god of healing, whereas Hermes was the protector of merchants and thieves, but both symbols have ancient roots. The staff of Asclepius, entwined by a single snake, was part of the crest of the U.S. Surgeon General's office in the early 19th century, but it was replaced in 1871 by the caduceus, perhaps partly because of an aesthetic preference for the latter's symmetry. Both symbols are used today by various medical services. 1- In Greek mythology, Hermes (Roman, Mercury), the son of Zeus and Maia, was a ubiquitous and agile deity with many functions: protector of flocks and shepherds; guide and protector of travelers; conductor of souls to the underworld; a messenger of Zeus; bringer of good luck; and patron of orators, writers, athletes, merchants, and thieves. Known for his ingenuity, speed, and protectiveness, he was usually pictured with a broad-rimmed hat with wings on it, a herald's staff (caduceus), winged sandals, a ram, a lyre, and a shepherd's staff. Because his interests were broad and always changing, he was one of the most loved of the Olympian gods. Various attributes and activities of Hermes are mentioned in the Homeric Hymn to Hermes, the Homeric Hymn to Demeter, Homer's Iliad, and Vergil's Aeneid. 2- Thoth was the Greek name for the Egyptian deity Djhowtey, god of learning, wisdom, and magic. In late Egyptian mythology he was the creator and orderer of the universe and the inventor of writing, arithmetic, and astronomy. Thoth was depicted as an ibis-headed man carrying a pen and an ink holder or as a dog-headed baboon. In the Hellenistic period he was identified with the Greek god Hermes and in later European lore with Hermes Trismegistus, patron of magicians. " The Book of Thoth " is a traditional name for tarot cards.